The present invention relates generally to displaying medical digital images in a graphical user interface of a data processing system, and more specifically, to automatic viewport releveling in the graphical user interface of the data processing system.
In a typical example, a medical digital image may be produced as a result of a computed tomography (CT) scan comprises a matrix of pixels with each pixel having a CT number, that is converted into a visible image of grey shades. The visible image thus created depends upon settings for a window width, a window level, zoom control and other factors. An area of the medical digital image that is actually displayed is controlled by the zoom control.
Using the example above, the window width is a range of CT numbers displayed using shades of gray, ranging from black to white. CT numbers greater than the window width are displayed as white, while CT numbers, less than the window width, are displayed as black. The window width control adjusts a range of CT numbers that are displayed with contrast. Reducing the window width increases the image contrast. The window level defines a center of the scale of the range of CT numbers. The CT scan has very high contrast sensitivity enabling a window setting to enhance very small density differences for scanned tissues. Because a CT machine can detect a difference in scanned tissues of less than 1% a small density resolution difference, as measured by the CT scan, is exaggerated to permit viewing on a display of a computer by users that do not have a capability to perceive the subtle differences produced.
When displaying the medical digital image, pixel values represented in a computer typically in a range of values between 0 and a predetermined maximum are allocated a particular brightness value for rendering on a display of the computer. A correspondence between the pixel values and display brightness levels is typically achieved using a look up table, which in some cases is a simple linear translation. Using the lookup table, each pixel provided in an input image is mapped or transformed to a corresponding pixel in an output image to specify a new pixel value in place of an original pixel value. Previous examples of displaying medical digital images, including viewing a CT scan, in which window/level parameters are critical to a practitioner's ability to discern features of interest, typically compute image features across a breadth of the image. However, when computed image-wide, local features are typically not presented with sufficient relief, and often introduce a significant delay during refreshing.
In another previous example of displaying a medical digital image, a display comprises three rows of images in which each row is a slice sequence of a particular scan from a number of slices. A middle row, deemed a primary row, contains a scan selected by a user at a time tn, a corresponding top row contains scans from a time tn−1 and a corresponding bottom row contains scans from a time tn+1. The images are displayed in a fixed grid arrangement.
In another previous example of displaying a medical digital image, use of a zoom tool displays an image, which is a smaller region of a corresponding high-resolution full size image. In yet another previous example of displaying a medical digital image, sub-regions of a larger high-resolution image have not been allocated sufficient contrast so that all contours and image features are visible.
In yet another previous example of displaying a medical digital image, visualizing a region of interest within a viewport presents image data as an image in the viewport using a set of global image processing operations and a viewing window in the viewport. A second and different set of image processing operations is provided for the viewing window that reduces image artifact with respect to a desired structure of interest in the viewing window in the viewport.
In yet another previous example of displaying a medical digital image, display mode data for each classified kind of a medical image indicates, based on the positions of the medical images set in the display mode by the user, at least a number of screen divisions, display positions formed by the screen divisions, and an indication of the classified kind of each of plural of medical images formed within the screen divisions. Each display position corresponds to a single classified kind of medical image when medical images corresponding to different classified kinds are concurrently displayed on a screen. An image display unit is configured to display respective medical images included in obtained image files on the screen in accordance with display mode data added in the obtained image files.
Within a context of these previous examples, general releveling tools are known, however none typically provide additional insight available for local features needed to discern the features of interest.